1. Field of the Invention
This invention relates generally to disk mass storage subsystems and more specifically to the formatting of a complete track during a single revolution of the disk.
2. Description of the Prior Art
Many computing systems of the early 1950's used magnetic drum storage for their data files, particularly in airline reservation and banking applications. The data was processed by one read/write head per track. Bit densities were in the order of 100 bits per inch.
Magnetic disk storage was developed to improve the volumetric efficiency by storing bits on the disk surfaces rather than the periphery of a drum and have a single head per disk floating within microinches of the disk surface. This allowed the track density to be increased to in excess of 2,000 bits per inch.
The addressing of data now had to include the selecting of a cylinder (comparable track positions on each surface), a read/write head, and a sector within a track. Each track must include this addressing information to assure that the correct sector is addressed.
Today's disk devices are either hard sector devices or soft sector devices. The hard sector device is prepared by the supplier in a fixed format to which the system designer must conform. The soft sector device is formatted by the system designer and may be rewritten at will.